Prepare XMRig-HAC fork for public release

- Add DragonX coin and rx/hush algorithm support
- Update branding to XMRig-HAC / dragonx.is
- Update repository URLs to git.hush.is
- Replace example wallet addresses with placeholders
- Update .gitignore for build directories
- Document fork changes in README and CHANGELOG

.gitignore

@@ -1,4 +1,6 @@
 /build
+/build-windows
+/deps-windows
 scripts/build
 scripts/deps
 /CMakeLists.txt.user